A motor operation controller, which can accommodate different power supply voltages by changing a minimum circuit configuration using common motors, wiring, etc., has an insulation structure between input power supply and the motors for providing the capability of bidirectional operation in a power mode and a regeneration mode. The motor operation controller comprises a converter section and an inverter section for supplying power to a motor. In the converter section, there is an insulation type bidirectional DC voltage conversion function provided by an insulation type bidirectional DC voltage conversion section 32 having an insulation type bidirectional DC voltage converter 33, a controller 35, and a smoothing circuit 34.